Enable Advanced Performance

The risk you run is basically if you lose power while writing to your HDD, you'd lose that data, but that really isn't any different than writing directly to the HDD really. The risk is higher, but this is a problem even with all cache disabled (obviously loss of power results in loss of unsaved data or data that has not been completely written to disk).

As for it's functional benefit, I'd say it generally isn't worthwhile. When loading/playing games and most other applications, reading speed / seek time are what determine how fast and responsive your system feels. Rarely does writing play into overall system performance. General computer usage involves very low amounts of writing compared to reads - both in raw number of writes and size. This only provides real benefit if for some reason you are writing large amounts of data to disk consistently. Otherwise this change will largely go unnoticed.